Tuesday, July 3, 2018

Season 12 superfinal, games 71-74

After 74 games Stockfish leads 20-7 with 47 draws. The draw rate continues to be low, now at 63.5%. Stockfish added two wins, both in the same opening. This is a rare event in superfinals.

There was a material imbalance of BN vs R early in game 36.1, with the engines castling in opposite directions.

Both engines focused on the queen side. Stockfish created a pawn majority there, capturing a pawn. Komodo placed its major pieces on the open files and Stockfish had to keep its king safe. As the engines exchanges pieces the evals started to increase, Stockfish captured a second pawn and made passers out of its queen side pawns. Komodo captured on the king side, after another piece exchange only QBN vs QR remained.

The white a pawn started to march forward slowly, Stockfish used its pieces to support it while protecting its king. Komodo tried but couldn't stop the advancing pawn, on move 53 it reached the 6th rank.

The white pawn made another step forward and Komodo blocked with its rook. The black queen tried to attack the white king but it was not strong enough on its own. In the end Komodo was forced to lose its rook to stop the pawn, a win for Stockfish.

In game 36.2 the engines again castled in opposite directions. Stockfish opened the queen side and Komodo pushed pawns on the king side, yet both kings remained relatively safe. Evals remained close to 0 despite Komodo being a pawn up. There were many pieces left on the board in an open position but the engines could not find an effective way to attack.

The engines shuffled for 20 moves, then Stockfish moved its pawns on the king side and evals became negative and started to increase. After a few exchanges Stockfish had the bishop pair advantage, its pieces had a lot of space and it had a strong pawn formation on the king side.

The black king captured the h6 pawn, it did not need a shield anymore and it moved forward to support the pawns. After a pawn exchange Stockfish had a connected pair of passers on the king side. Komodo had to give a rook to take out one of the bishops, in an attempt to stop the passers from marching.

Stockfish was too strong. It drove the blocking knight away and then the pawns pushed forward, winning the game. An incredible double win for Stockfish in this opening.

Stockfish started game 37.1 with an eval close to 1. Komodo pushed pawns in the center, getting a pawn to e3 and a knight to f2, right in front of the white king. Through piece exchanges Stockfish had a passer on the e file as well. Stockfish avoided a repetition draw and took out the advanced pawn and knight for a rook. The game reached a QRN vs QRR position, evals fell to 0 as Komodo gave back the material and reduced to a drawn rook ending. In the reverse game 37.2 Komodo created a central passer and pushed it to the 6th rank. The engines focused their pieces around the passer, after a series of exchanges Stockfish removed it with QRB vs QRB remaining. The engines exchanged rooks and started to shuffle. After 20 moves Komodo captured a pawn and exchanged queens. This left an opposite color bishop ending, and though Komodo was two pawns up it couldn't convert the win. The engines wouldn't lower their evals, the game continued until move 145.